Rock-drill.



No. 196,891. PATENTED AUG. 8, 1905. J. T. BLAGKETT. RQOK DRILL.

APPLICATION FILED SEPT. 15-. 1909.

2 SHBETS8HEET 1.

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No. 796,891. PATENTED AUG. 8, 1905. J. T. BLAGKETT.

ROCK DRILL.

APPLICATION FILED SEPT. m. 1904.

2 SHEETS-SHEET 2.

fnrenfor UNITED STATES PATENT OFFICE.

ROCK-DRILL.

Specification of Letters Patent.

Patented Aug. 8, 1905.

Application filed September 15, 1904:- Serial No. 224,597.

To all whom it may concern:

Be it known that LJOHN THoMAs BLAOKETT, a subject of the King of Great Britain and Ireland, residing at Ivy House, Guisb'orough, in the county of York, England, (whose .postofiice address is Ivy House, Guisborough, in the county of York, England,) have invented certain new and useful Improvements in Rock- Drills; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in rock-drills and the like; and it consists principally in'means whereby when the drill or cutting-tool meets an obstruction in the material on which it is operating-for instance, an extra hard piece of rockso as to prevent its forward feed, it is automatically drawn backward in the bore-hole and automatically fed forward again, such automatic withdrawal and refeed being repeated until the drill-point clears the obstruction, when the drill will be continuously fed forward to its work by means of the feed mechanism. The mechanism for effecting the automatic withdrawal and refeed of the drill may be employed for such purpose only in conjunction with any known or suitable clutch mechanism and gearing for effecting the ordinary feed and withdrawal of the drill, or it can be employed for both the automatic withdrawal and refeed and as the driving-clutch forthe ordinary feed and withdrawal of the drill-spindlefor instance, by means of an ordinary clutch-lever as now employed in rock-drilling machines.

In the accompanying drawings, Figure 1 is a sectional elevation illustrating the invention applied to motor-driven rock-drilling mechanism in which a clutch-pinion is employed for throwing the screw-bar or drill-spindle into and out of gear with. the driving-shaft. Fig. 2 is a sectional elevation showing the automatic withdrawal and refeeding mechanism adapted to act as the clutch in place of the clutch-pinion of Fig. 1 for throwing the screw-bar or drill-spindle into and out of gear with the driving-shaft and mechanism. Fig. 3 is a detail view of the lever and parts connected thereto for actuating the toothed sleeve (hereinafter described) of the automatic withdrawing and refeeding mechanism as the driving-clutch for ordinary working. Fig. 4 is a part-sectional elevation of Fig. 1, showing the form of the teeth on the sleeve D, hereinafter described, and also showing the corresponding teeth on the boss 9 of the gearwheel G, hereinafter referred to. Fig. 5 is a cross-section of the sleeve D and of the boss of gear-wheel Gr, taken on line 1 2 of Fig. 1. Fig. 6 is a similar view of Fig. 5, but shows only one tooth on the sleeve and one' tooth on the boss of the gear-wheel. Fig. 7 is an elevation showing more clearly the form of the teeth on sleeve D and on the boss of gearwheel' G. p

The same reference-letters indicate corresponding parts in the different figures of the drawings.

Referring to Fig. l, the motor and mechanism for actuating the screw-bar or drillspindle are inclosed in the casing, (markedA.) The screw-bar B, which carries the drill at its forward end in the usual socket, is rotated through a train of gear-wheels by means of a sleeve (1, having a feather or key 0 which works in a keyway in the screw-bar, said sleeve 0 being itself driven by an outer sleeve or collar D, keyed on the inner sleeve by key (Z in such a way that it is capable of sliding longitudinally on said inner sleeve G. The outer sleeve D has a suitable number of teeth E (or it might be a single tooth, as hereinafter explained) of wide pitch on one of its ends, (for instance, the forward end, as shown,) which teeth E are normally held in engagement by means of a spring F or its equivalent, with corresponding teeth a, formed on or attached to the boss 9 of the gear-Wheel G, which is loosely mounted on the inner sleeve C and is driven by pinion H, slidably keyed on a shaft or spindle 1, arranged parallel with the screw-bar B. The pinion-shaft and pinion H are driven by the driving-shaft J of a compressed-air or other motor by means of another gear-wheel K, fixed on shaft I, said wheel K being driven by pinion Q (shown in dotted lines) on the shaft J of the motor. The motor I prefer to employ for actuating the drill-gearing described herein is a reversible compressed-air motor, which may be of any known or convenient typefor instance, as shown and described in the prior British speciiication of Letters Patent No. 2,394 of 1899. The feed and withdrawal of the drill-spindle or screw-bar B in the ordinary working is effected by means of the feed-nut L, working v on the screw-bar, which feed-nut is driven by another toothed pinion M, keyed on the abovementioned pinion-shaft l, engaging the teeth of a gear-wheel N on the feed-nut. Means are provided for adjusting the above-mentioned spring F, which acts on the outer toothed sleeve D. For instance, the spring may be a spiral spring, as shown, operatingon the rear end of said sleeve D and surrounding the inner sleeve C, on which latter a screw nut or collar 0 isprovided behind spring F for adjusting the tension thereof. P is a lock-nut acting in conjunction with nut O for adjusting the spring F. The pinion H acts as the driving-clutch for actuating the drill mechanism, said pinion being provided with a clutch-collar it of known form, with'which a clutch-lever R (also of known form) engages. The gear-wheels and pinions, as above described and shown in the drawings, are so arranged as to cause the screw-bar to revolve faster than the feed-nut for eifecting the forward feed of the screw-bar and drill, the pinion H being larger than pinion M and gearwheel G smaller than gear-wheel N. For effecting the withdrawal or backward movement of the drill during ordinary working (that is, when the drill meets with no abnormal obstruction) the clutch-lever R would be operated so as to disengage the teeth of pinion H from the teeth of gear-wheel G, whereby the rotation of the screw-bar is stopped, and as the motor continues to drive the pinion-shaft I the pinion M thereon continues to rotate gear-Wheel N and feed-nut L, so that the drill will be withdrawn from the borehole. By operating the clutch-lever R in the reverse direction, so as to cause pinion H to again engage gear-wheel Gr, the screw-bar and drill will be again fed forward.

Referring to Figs. 2 and 3, which show an arrangement of the mechanism wherein the toothed sleeve D is employed as the drivingclutch (in addition to its use for automatic withdrawal and refeeding of the drill, as dedescribed) for actuating the drill-gear in the ordinary or normal Working, instead of employing the clutch-pinion H, as in Fig. 1, it will be seen that the inner sleeve (1 of Fig. 1 is omitted and that the position of the toothed sleeve D and its form are somewhat altered. In this figure also pinion H does not act as a clutch-pinion, but is fixed on shaft 1, and the clutch-lever R is arranged to operate toothed sleeve D as the clutch for working the drill mechanism during the ordinary or normal working. It will be seen that the gear-wheel G in Fig. 2 is formed or provided with an elongated boss or sleeve, (marked 9,) the rear end of which is provided with a tooth (or teeth, as the case may be) adapted to engage a corresponding tooth (01' teeth) E on sleeve D, which latter is normally held in engagement with the tooth or teeth on the boss of sleeve G by means of spring F. The collar T is screwed into the rear end of casing A, and the lever R is pivoted on said collar T, as shown in Figs. 2 and 3. The short arms U on lever R are each preferably formed with a flat surface V, and said flat surfaces bear on a collar ornut W, screwed onto sleeve D. The tension of spring F can be adjusted by turning the collar T so as to screw it in or out of the casing A, the nut W of course being correspondingly turned, so as to bring it into operative contact with the clutch-lever R.

The action of the automatic withdrawal and refeed is the same in the mechanisms of both Figs. 1 and 2namely, when the advancement of the drill is stopped or retarded, as by an obstruction, the teeth 0 (or tooth, as the case may be) on the boss g of wheel G will ride up over the inclined engaging surfaces of the corresponding teeth E on the sleeve D, which sleeve is thus forced back against spring F. Owing to the disengagement of the teeth 6 E the wheel G will'be revolved freely and the sleeves C and D will remain stationary, so that the rotation of the screw-bar B and its forward feed will be stopped. As, however, the feed-nut L continues to he revolved by means of pinion M and gearwheel N,the screwbar B, and consequently the drill, will be drawn back toward the right, and this backward movement will continue until the teeth E on sleeve D are again forced into engagement with the corresponding teeth 0 on the boss of wheel Gr, whereupon the sleeve D, and consequently the sleeve C and screw-bar B, will be again rotated in the right-hand or forward direction, so as to again feed the drill forward. This automatic Withdrawal and refeed continues as long as the obstruction to the normal feed remains. When the obstructi n is removed, the spring F holds the teeth E on the sleeve in engagement with those on the boss of the gear-Wheel Gr, so that the latter will be able to rotate the screw-bar B, which by means of the feed-nut will again advance the drill into the material as it is cut.

The distance the drill will be withdrawn when its forward feed is prevented by an obstruction will depend on the number of teeth, respectively, on the sleeve D and on the boss of the gear -wheel G. For instance, if the maximum automatic withdrawal is required when an obstruction occurs'only one tooth would be provided on said sleeve D and on the boss of wheel G, whereby when said gearwheel slips it will have to turn once round before again engaging the tooth on the said sleeve. It will be readily understood that if after such slipping action the obstruction continues the tooth will be again slipped and the drill-spindle or screw-bar will be again drawn back.

By employing a reversible motor if the drill has been withdrawn from the bore-hole for instance, for the purpose of inserting another drill-said drill may be rapidly moved up to its work again by simply reversing the motor, as by keeping the driving-clutch H or toothed sleeve D out of operative connection when the motor is reversed the motion of the pinion and gear-wheel operating the feed-nut, and consequently the rotation of the feednut will be reversed, and will thus quickly feed the screw-bar and drill forward.

The engaging faces of the teeth on the outer sleeve and on the boss of the gear-wheel on the inner sleeve are formed sloping, as will be seen in reference to Figs. Lto 7, inclusive.

So far as I am aware I am the first to provide a machine of the kind set set forth whereby when the drill or cutting-tool meets an unduly hard substance or great resistance it is automatically drawn back in the borehole and automatically fed forward again until the obstruction is removed, when the drillspindle and screw-bar will be automatically fed forward again as in normal working.

What I claim, and desire to secure by Letters Patent, is

1. The combination, with a screw-threaded drill-bar, of a feed-nut engaging with the said drill-bar, a wheel mounted concentric with the said drill-bar, driving devices for revolving the said nut and wheel, a sleeve which revolves with the said drill-bar and which is slidable longitudinally of it, clutch members on the said ,wheel and sleeve, means for moving the said clutch members out of engagement automatically when the drill encounters a prearranged resistance, and a spring which normally holds the said clutch members in engagement.

2. The combination, with a screw-threaded drill-bar, of a feed-nut engaging with the said drill-bar, a wheel mounted concentric with the said drill-bar, driving devices for revolving the said nut and wheel, a hand-operated clutch mechanism for disengaging the said wheel from its driving device without disengaging the said feed-nut, a sleeve which revolves with the said drill-barand which is slidable longitudinally of it, clutch members on the said wheel and sleeve, means for moving the said clutch members out of engagement automatically when the drill encounters a prearranged resistance, and a spring which normally holds the said clutch members in engagement.

In testimony whereof I affix my signature in presence of two witnesses.

' JOHN THOMAS BLAGKETT.

Witnesses:

J. GROOM, W. H. LINSON. 

